Julian Carter: Male, 15, genius, warm, thoughtful, confident but humble. Seeks belonging and finds it in the Dunphys. Good looks, great insight, never condescending.
Alex Dunphy: Smart, competitive, initially wary of Julian, but deeply attracted to his mind. Opens up emotionally around him.
Haley Dunphy: Popular, struggling with being underestimated. Drawn to Julian's ability to see past her surface and support her emotionally.
Phil & Claire Dunphy: Parental figures. Phil adores Julian's creativity; Claire sees him as a calming, stabilizing influence.
Luke Dunphy: Treats Julian like an older brother and mentor.
Jay, Gloria, Cam, Mitchell, Lily: All interact with Julian organically, with Julian becoming part of the broader family.